Thioalkenylphosphonic acid ester and process for the preparation thereof

ABSTRACT

A phosphonic acid ester compound of the formula: 
     
       
         R 1 C(SR 3 )═CHP(═O)(OR 2 ) 2    
       
     
     or 
     
       
         [P(═O)(OR 2 ) 2 ]CH═C(SR 3 )—R 4 —C(SR 3 )═CH[P(═O)(OR 2 ) 2 ] 
       
     
     wherein R 1  represents a monovalent group selected from hydrogen, alkyl, cycloalkyl, cycloalkenyl, aryl, aralkyl, alkenyl and silyl, R 2  and R 3  each represent aryl and R 4  represents alkylene or cycloalkylene. The ester compound is produced by reaction of an acetylene compound, R 1 C≡CH or HC≡C—R 4 —C≡CH, with with a phosphorothioate, (R 2 O) 2 P(═O)SR 3 , in the presence of a palladium complex catalyst.

BACKGROUND OF THE INVENTION

This invention relates to a thioalkenyl phosphonic acid ester and to aprocess for the preparation thereof.

Thioalkenyl phosphonic esters are a group of compounds useful asintermediate compounds for the production of fine chemicals, becausethey can easily give, by Michael reaction with a nucleophile, acarbanion which in turn causes Horner-Emmons addition reaction with acarbonyl compound and because they can undergo a carbon—carbonbond-forming reaction by regio- or stereo-selective coupling with avinyl halide, an aryl halide or Grignard reagent in the presence of atransitional metal catalyst.

At present, no methods have been known which can produce thioalkenylphosphonic esters by a single stage reaction of a hydrocarbon. Areaction of a thioalkenyl halogen compound with a secondary phosphiteunder basic conditions may yield a thioalkenyl phosphonic ester. Anaddition of a secondary phosphite to a thioalkyne may also produce athioalkenyl ether. These methods, however, are not advantageous from theindustrial point of view, because the sulfur-containing raw materialsare not easily obtainable.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide a simpleprocess which can produce a thioalkenyl phosphonic ester at low costsusing an easily feasible starting material.

Another object of the present invention is to provide a novelthioalkenyl phosphonic ester.

In accordance with one aspect of the present invention, there isprovided a process for the preparation of a thioalkenylphosphonic acidester of the following formula (I):

R¹C(SR³)═CHP(═O)(OR²)₂  (I)

wherein R¹ stands for a monovalent group selected from hydrogen atom, analkyl group, a cycloalkyl group, a cycloalkenyl group, an aryl group, anaralkyl group, an alkenyl group and a silyl group, R² stands for an arylgroup and R³ stands for an aryl group, comprising reacting an acetylenecompound of the following formula (II):

R¹C≡CH  (II)

wherein R¹ is as defined above, with a phosphorothioate of the followingformula (III):

(R²O)₂P(═O)SR³  (III)

wherein R² and R³ are as defined above, in the presence of a palladiumcomplex catalyst.

In another aspect, the present invention provides a process for thepreparation of a bis(thioalkenyl)phosphonic acid ester of the followingformula (IV):

[P(═O)(OR²)₂]CH═C(SR³)—R—C(SR³)═CH[P(═O)(OR²)₂]  (IV)

wherein R² stands for an aryl group, R³ stands for an aryl group and R⁴stands for an alkylene group or a cycloalkylene group, comprisingreacting an acetylene compound of the following formula (II):

HC≡C—R⁴—C≡CH  (V)

wherein R⁴ is as defined above, with a phosphorothioate of the followingformula (III):

(R²O)₂P(═O)SR³  (III)

wherein R² and R³ are as defined above, in the presence of a palladiumcomplex catalyst.

The present invention also provides a thioalkenylphosphonic acid esterof the following formula (I):

R¹C(SR³)═CHP(═O)(OR²)₂  (I)

wherein R¹ stands for a monovalent group selected from hydrogen atom, analkyl group, a cycloalkyl group, a cycloalkenyl group, an aryl group, anaralkyl group, an alkenyl group and a silyl group and R² stands for anaryl group and R³ stands for an aryl group.

The present invention further provides a bis(thioalkenyl)phosphonic acidester of the following formula (IV):

[P(═O)(OR²)₂]CH═C(SR³)—R⁴—C(SR³)═CH[P(═O)(OR²)₂]  (IV)

wherein R⁴ stands for an aryl group, R³ stands for an aryl group and Rstands for an alkylene group or a cycloalkylene group.

Other objects, features and advantages of the present invention willbecome apparent from the detailed description of the preferredembodiments of the invention to follow.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

The phosphorothioate used as a raw material in the process of thepresent invention is represented by the formula (III):

(R²O)₂P(═O)SR³  (III)

wherein R² and R³ each stand for an aryl group preferably having 6-14carbon atoms, more preferably 6-12 carbon atoms. Illustrative ofsuitable aryl groups are phenyl, tolyl and napththyl.

The phosphorothioate is reacted with an acetylene compound of theformula (II) or (V)

R¹C≡CH  (II)

HC≡C—R⁴—C≡CH  (V)

wherein R¹ stands for a monovalent group selected from

(a) hydrogen atom,

(b) an alkyl group preferably having 1-18 carbon atoms, more preferably1-10 carbon atoms, such as methyl, ethyl, propyl, butyl, hexyl octyl ordecyl,

(c) a cycloalkyl group preferably having 5-18 carbon atoms, morepreferably 5-10 carbon atoms, such as cyclohexyl, cyclooctyl orcyclododecyl,

(d) a cycloalkenyl group preferably having 5-18 carbon atoms, morepreferably 5-10 carbon atoms, such as cyclohexenyl, cyclooctenyl orcyclododecenyl,

(e) an aryl group preferably having 6-14 carbon atoms, more preferably6-10 carbon atoms, such as phenyl, naphthyl, substituted phenyl (e.g.tolyl or benzylphenyl) or substituted naphthyl (e.g. methylnaphthyl),

(f) an aralkyl group preferably having 7-13 carbon atoms, morepreferably 7-9 carbon atoms, such as benzyl, phenethyl, phenylbenzyl,naphthylethyl or naphthylmethyl,

(g) an alkenyl group preferably having 2-18 carbon atoms, morepreferably 2-10 carbon atoms, such as vinyl, propenyl or 3-butenyl and

(h) a silyl group which may have 1-3 substituents such as a hydrocarbylgroup having 1-18 carbon atoms, preferably 1-8 carbon atoms, such as analkyl (e.g. methyl, ethyl, propyl, butyl or octyl), cycloalkyl (e.g.cyclohexyl), aryl (e.g. phenyl, tolyl, naphthyl) or aralkyl (e.g.benzyl, phenethyl or naphthylmethyl), and R⁴stands for

(i) an alkylene group preferably having 1-20 carbon atoms, morepreferably 1-10 carbon atoms, such as methylene or tetramethylene, or

(j) a cycloalkylene group preferably having 5-18 carbon atoms, morepreferably 5-10 carbon atoms, such as cyclopentylene or cyclohexylene.

Illustrative of suitable acetylene compounds are non-substitutedacetylene, butyne, octyne, phenylacetylene, trimethylsilylacetylene,1,8-nonadiyne, diethynylbenzene, hexynenitrile andcyclohexenylacetylene. It is without saying that the present inventionis not limited to these acetylene compounds.

The above reaction is performed in the presence of a palladium complexcatalyst.

Any known palladium complex catalyst may be used. Low valency palladiumcomplexes, inclusive of zero-valent complexes, may be suitably used. Lowvalency palladium complexes having a tertiary phosphine or a tertiaryphosphite as a ligand are especially suitably used.

In this case, a precursor substance which can form in situ a low valencypalladium complex having a tertiary phosphine or a tertiary phosphite asa ligand during the reaction of the acetylene compound with thesecondary phosphite may also be suitably used. For example, a palladiumcomplex containing neither tertiary phosphine nor tertiary phosphite maybe used in conjunction with a tertiary phosphine or a tertiary phosphiteso that a low valency palladium complex having a tertiary phosphine or atertiary phosphite as a ligand is formed in the reaction mixture.Further, a palladium complex containing a tertiary phosphine or tertiaryphosphite may be used in conjunction with another tertiary phosphine oranother tertiary phosphite.

A tertiary phosphine of the following formula may be suitably used as aligand of the palladium complex catalyst:

wherein R⁵, R⁶ and R⁷ are each

(k) an alkyl group preferably having 1-18 carbon atoms, more preferably1-12 carbon atoms, such as methyl, ethyl, propyl, butyl, hexyl octyl ordecyl,

(l) a cycloalkyl group preferably having 4-6 carbon atoms, morepreferably 5-6 carbon atoms, such as cyclopentyl or cyclohexyl,

(m) an aryl group preferably having 6-14 carbon atoms, more preferably6-10 carbon atoms, such as phenyl, naphthyl, substituted phenyl (e.g.tolyl or benzylphenyl) or substituted naphthyl (e.g. methylnaphthyl), or

(n) an aralkyl group preferably having 6-13 carbon atoms, morepreferably 6-10 carbon atoms, such as benzyl, phenethyl, phenylbenzyl ornaphthylmethyl.

Examples of the tertiary phosphines include triphenylphosphine,tris(4-chlorophenyl)phosphine, tris(4-fluorophenyl)phosphine,tritolylphosphine, diphenylmethylphosphine, phenyldimethylphosphine,diphenylcyclohexylphosphine and phenyldicyclohexylphosphine.

Illustrative of suitable palladium complex catalysts containing atertiary phosphine are tetrakis(triphenylphosphine)palladium,tris(triphenylphosphine)palladium, andethylenebis-(triphenylphosphine)palladium.

A tertiary phosphite of the following formula may be suitably used as aligand of the palladium complex catalyst:

wherein R⁵, R⁶ and R⁷ are as defined above.

Examples of the tertiary phosphites include trimethylphosphite andtriphenylphosphite.

Palladium complex catalysts containing other ligands than tertiaryphosphine or tertiary phosphite, such asbis(dibenzylideneacetone)palladium or palladium acetate, may also used,preferably in conjunction with the palladium complex catalyst containingtertiary phosphine or phosphite, for the purpose of the presentinvention.

The palladium complex catalyst is used in a catalytically effectiveamount and, generally, in an amount of up to 20 mole %, based on theacetylene compound. The acetylene compound and the phosphorothioate aregenerally used in a stoichiometric amount. However, the use of theacetylene compound or the phosphorothioate in a stoichiometricallyexcess amount does not adversely affect the desired reaction.

The reaction may be carried out with or without using a solvent. Thesolvent, when used, may be a hydrocarbon solvent or an ether solvent.The reaction is generally performed from room temperature to about 300°C., preferably 50-150° C. It is preferred that the reaction be carriedout in an oxygen-free atmosphere, such as in the atmosphere of nitrogen,argon or methane.

After the termination of the reaction, the product can be separated byany known manner such as chromatography, distillation andrecrystallization.

The following examples will further illustrate the present invention.The symbol Ph represents a phenyl group, t-Bu represents a t-butylgroup, Me represents a methyl group and n-Bu represent a n-butyl group.

EXAMPLE 1

To 2 ml of toluene were added 2 mmol of 1-octyne, 2 mmol of PhSP(O)(OPh)₂ and 2 mol % of Pd(PPh₃)₄ (tetrakis(triphenylphosphine)palladium)and the mixture was reacted at 100° C. for 5 hours in the atmosphere ofnitrogen. The reaction mixture was concentrated and separated by liquidchromatography to isolate diphenyl (Z)-2-phenylthio-1-octenylphosphonatewith a yield of 92%. The physical properties of the novel product aregiven below.

¹H-NMR (CDCl₃): δ 7.15-7.41 (m, 15H), 5.81 (d, 1H J_(H-P)=17.3 Hz), 2.12(t, 2H, J=7.6 Hz), 1.32-1.60 (m, 2H), 1.12-1.24 (m, 2H), 1.04-1.09 (m,4H), 0.80 (t, 3H, J=7.0 Hz);

¹³C-NMR (CDCl₃): δ 165.3, 150.6 (J_(C-P)=8.3 Hz), 134.7, 130.9, 129.6,129.2, 129.1, 124.9, 120.7 (J_(C-P)=4.1 Hz), 110.6 (J_(C-P)=197.6 Hz),38.2 (J_(C-P)=19.7 Hz), 31.3, 28.5, 28.2, 22.4, 14.0

³¹P-NMR (CDCl₃): δ 8.3

IR (liquid film): 2932, 2860, 2593, 1491, 1272, 1216, 1193, 1164, 1071,1025, 930, 754 cm⁻¹

Elementary analysis (as C₂₆H₂₉O₃PS)

calculated: C, 69.00; H, 6.46

measured: C, 69.06; H, 6.72

HRMS (EI, 70 eV):

calculated: 452.1575

measured: 452.1577

EXAMPLES 2-15

Example 1 was repeated in the same manner as described except that theacetylene compounds shown below were each used in lieu of 1-octyne toproduce novel thioalkenylphosphonic acid esters shown below. The yieldand physical properties of the esters are summarized below.

EXAMPLE 2

Acetylene compound:

Product:

Yield: 65%

¹H-NMR (CDCl₃): δ 7.09-7.42 (m, 15H), 6.57 (d, 1H, J_(H-P)=17.6 Hz),1.14 (s, 9H);

³¹P-NMR (CDCl₃): δ 6-8

IR (liquid film): 2972, 1591, 1491, 1276, 1214, 1191, 1164, 1027, 926,748 cm⁻¹

Elementary analysis (as C₂₄H₂₅O₃PS)

calculated: C, 67.91; H, 5.94

measured: C, 68.21; H, 6.14

HRMS (EI, 70 eV):

calculated: 424.1262

measured: 424.1172

PRODUCT OF EXAMPLE 3

Acetylene compound:

Product:

Yield: 90%

¹H-NMR (CDCl₃): δ 7.14-7.36 (m, 30H), 5.74 (d, 2H, J_(H-P)=17.4 Hz),2.00 (t, 4H, J=7.0 Hz), 1.13-1.19 (m, 4H), 0.79-0.83 (m, 2H);

³¹P-NMR (CDCl₃): δ 8.1

IR (liquid film): 2938, 1591, 1491, 1270, 1191, 1164, 1025, 928, 754cm⁻¹

Elementary analysis (as C₄₅H₄₂O₆P₂S₂)

calculated: C, 67.15; H, 5.26

measured: C, 67.39; H, 5.41

FAB-MASS (EI, 70 eV): 804 (M+)

PRODUCT OF EXAMPLE 4

Acetylene compound:

Product:

Yield: 87% (96/4)

¹H-NMR (CDCl₃): δ 6.97-7.41 (m, 20H), 6.12 (d, 1H, J_(H-P)=17.6 Hz);

³¹P-NMR (CDCl₃): δ 7.3

IR (liquid film): 3062, 2928, 1593, 1555, 1,491, 1441, 1274, 1191, 1027,926, 758, 690 cm⁻¹

Elementary analysis (as C₂₆H₂₁O₃PS):

calculated: C, 70.26; H, 4.76

measured: C, 70.29; H, 4.94

HRMS (EI, 70 eV):

calculated: 444.0949

measured: 444.0902

PRODUCT OF EXAMPLE 5

Acetylene compound:

Product:

Yield: 71% (93/7)

¹H-NMR (C₆D₆): δ 7.08-7.33 (m, 19H), 6.19 (d, 1H, J_(H-P)=17.0 Hz);

³¹P-NMR (CDCl₃): δ 6.8

IR (liquid film): 3,064, 1593, 1489, 1272, 1212, 1191, 1164, 1093, 1025,938, 768 cm⁻¹

Elementary analysis (as C₂₆H₂₀ClO₃PS)

calculated: C, 65.20; H, 4.21

measured: C, 64.90; H, 4.27

HRMS (EI, 70 eV):

calculated: 478.0559

measured: 478.0489

PRODUCT OF EXAMPLE 6

Acetylene compound:

Product:

Yield: 69% (91/9)

¹H-NMR (CDCl₃): δ 6.83-7.34 (m, 19H), 6.16 (d, 1H, J_(H-P)=17.0 Hz);

³¹P-NMR (CDCl₃): δ 7.1

IR (liquid film): 3066, 1597, 1491, 1274, 1212, 1191, 1162, 1025, 934,797, 766 cm⁻¹

Elementary analysis (as C₂₆H₂₀FO₃PS)

calculated: C, 67.52; H, 4.36

measured: C, 67.51; H, 4.40

HRMS (EI, 70 eV):

calculated: 462.0855

measured: 462.0799

PRODUCT OF EXAMPLE 7

Acetylene compound:

Product:

Yield: 89% (98/2)

¹H-NMR (CDCl₃): δ 6.97-7.33 (m, 19H), 6.20 (d, 1H, J_(H-P)=17.9 Hz),2.22 (s, 3H);

³¹P-NMR (CDCl₃): δ 7.6

IR (liquid film): 3062, 1593, 1551, 1491, 1274, 1212, 1191, 1164, 1025,932, 766 cm⁻¹

Elementary analysis (as C₂₇H₂₃O₃PS)

calculated: C, 70.73; H, 5.06

measured: C, 70.65; H, 5.07

HRMS (EI, 70 eV):

calculated: 458.1106

measured: 458.1096

PRODUCT OF EXAMPLE 8

Acetylene compound:

Product:

Yield: 84%

1H-NMR (CDCl₃): δ 7.06-7.50 (m, 15H), 5.88 (d, 1H, J_(H-P)=16.4 Hz),2.30 (t, 2H, J=7.0 Hz), 2.04 (t, 2H, J=7.3 Hz), 1.63-1.69 (m, 2H);

³¹P-NMR (CDCl₃): δ 6.9

IR (liquid film): 2928, 1591, 1491, 1270, 1191, 1164, 1025, 928, 754cm⁻¹

Elementary analysis (as C₂₄H₂₂NO₃PS):

calculated: C, 66.19; H, 5.09; N, 3.22

measured: C, 66.32; H, 5.16; N, 3.14

HRMS (EI, 70 eV):

calculated: 435.1058

measured: 435.1035

PRODUCT OF EXAMPLE 9

Acetylene compound:

Product:

Yield: 89%

¹H-NMR (CDCl₃): δ 7.15-7.46 (m, 15H), 5.94 (d, 1H J_(H-P)=17.4 Hz),3.55-3.68 (m, 2H), 2.39 (t, 2H, J=6.5 Hz), 1.82 (bs, 1H);

³¹P-NMR (CDCl₃): δ 7.4

IR (liquid film): 3416, 3062, 2932, 1591, 1491, 1249, 1212, 1191, 936,754 cm⁻¹

Elementary analysis (as C₂₂H₂₁O₄PS)

calculated: C, 64.07; H, 5.13

measured: C, 63.96; H, 5.16

HRMS (EI, 70 eV):

calculated: 412.0898

measured: 412.0902

PRODUCT OF EXAMPLE 10

Acetylene compound:

Product:

Yield: 85%

¹H-NMR (CDCl₃): δ 7.17-7.39 (m, 15H), 5.90 (d, 1H J_(H-P)=16.7 Hz), 3.26(t, 2H, J=6.7 Hz), 2.33 (t, 2H, J=7.0 Hz), 1.77-1.79 (m, 2H);

³¹P-NMR (CDCl₃): δ 7.6

IR (liquid film): 2962, 1591, 1491, 1270, 1214, 1191, 1025, 930, 752cm⁻¹

Elementary analysis (as C₂₃H₂₂ClO₃PS)

calculated: C, 62.09; H, 4.98

measured: C, 62.44; H, 5.06

HRMS (EI, 70 eV):

calculated: 444.0716

measured: 444.0698

PRODUCT OF EXAMPLE 11

Acetylene compound:

Product:

Yield: 68%

¹H-NMR (CDCl₃): δ 7.08-7.34 (m, 15H), 5.85 (d, 1H J_(H-P)=16.7 Hz), 3.97(t, 2H, J=7.0 Hz), 2.41 (t, 2H, J=7.0 Hz), 1.04 (s, 9H);

³¹P-NMR (CDCl₃): δ 6.9

IR (liquid film): 2976, 1729, 1591, 1491, 1280, 1214, 1191, 1162, 932,768 cm⁻¹

Elementary analysis (as C₂₇H₂₉O₅PS)

calculated: C, 65.31; H, 5.89

measured: C, 65.66; H, 6.14

HRMS (EI, 70 eV):

calculated: 496.1473

measured: 496.1425

PRODUCT OF EXAMPLE 12

Acetylene compound:

Product:

Yield: 91%

¹H-NMR (CDCl₃): δ 7.10-7.41 (m, 15H), 6.09 (bs, 1H), 6.04 (d, 1H,J_(H-P)=16.6 Hz), 1.92-1.97 (m, 4H), 1.31-1.34 (m, 4H);

³¹P-NMR (CDCl₃): δ 8.6

IR (liquid film): 3062, 2934, 1593, 1551, 1491, 1274, 1214, 1191, 1164,1027, 928, 766 cm⁻¹

Elementary analysis (as C₂₆H₂₅O₃PS)

calculated: C, 69.62; H, 5.62

measured: C, 69.58; H, 5.80

HRMS (EI, 70 eV):

calculated: 448.1262

measured: 448.1213

PRODUCT OF EXAMPLE 13

Acetylene compound:

Product:

Yield: 88%

¹H-NMR (CDCl₃): δ 7.07-7.36 (m, 15H), 6.16 (d, 1H J_(H-P)=17.7 Hz), 3.67(s, 2H), 3.11 (s, 3H);

³¹P-NMR (CDCl₃): δ 8.6

IR (liquid film): 3046, 2934, 1591, 1491, 1274, 1214, 1191, 1120, 930,756 cm⁻¹

Elementary analysis (as C₂₂H₂₁O₄PS)

calculated: C, 64.07; H, 5.13

measured: C, 64.35; H, 5.23

HRMS (EI, 70 eV):

calculated: 412.0898

measured: 412.0839

PRODUCT OF EXAMPLE 14

Acetylene compound:

Product:

Yield: 94%

¹H-NMR (CDCl₃): δ 7.15-7.38 (m, 15H), 6.54 (d, 1H J_(H-P)=20.1 Hz), 2.88(s, 2H), 2.19 (t, 4H, J 6.8 Hz), 1.14-1.15 (m, 8H), 0.82 (t, 6H, J=6.7Hz);

³¹P-NMR (CDCl₃): δ 10.0

IR (liquid film): 3064, 2960, 2866, 1593, 1491, 1274, 1216, 1193, 1164,930, 768 cm⁻¹

Elementary analysis (as C₂₉H₃₆NO₃PS)

calculated: C, 68.34; H, 7.12; N, 2.75

measured: C, 68.90; H, 7.39; N, 2.67

HRMS (EI, 70 eV):

calculated: 509.2154

measured: 509.2124

PRODUCT OF EXAMPLE 15

Acetylene compound:

Product:

Yield: 60%

¹H-NMR (CDCl₃): δ 7.14-7.36 (m, 15H), 6.43 (d, 1H J_(H-P)=22.9 Hz),−0.08 (s, 9H);

²⁹Si-NMR (CDCl₃): δ 4.4 (Jp-si =26.2 Hz)

IR (liquid film): 3064, 2960, 1593, 1491, 1272, 1251, 1212, 1191, 1164,930, 841, 793, 754 cm⁻¹

Elementary analysis (as C₂₃H₂₅O₃PSSi)

calculated: C, 62.70; H, 5.72

measured: C, 63.26; H, 5.60

HRMS (EI, 70 eV)

calculated: 440.1031

measured: 440.1035

What is claimed is:
 1. A process for the preparation of athioalkenylphosphonic acid ester of the following formula (I):R¹C(SR³)═CHP(═O)(OR²)₂  (I) wherein R¹ stands for a monovalent groupselected from hydrogen atom, an alkyl group, a cycloalkyl group, acycloalkenyl group, an aryl group, an aralkyl group, an alkenyl groupand a silyl group, R² stands for an aryl group and R³ stands for an arylgroup, comprising reacting an acetylene compound of the followingformula (II): R¹C≡CH  (II) wherein R¹ is as defined above, with aphosphorothioate of the following formula (III): (R²O)₂P(═O)SR³  (III)wherein R² and R³ are as defined above, in the presence of a palladiumcomplex catalyst.
 2. A process for the preparation of abis(thioalkenyl)phosphonic acid ester of the following formula (IV):[P(═O)(OR²)₂]CH═C(SR³)—R⁴—C(SR³)═CH[P(═O)(OR²)₂]  (IV) wherein R² standsfor an aryl group, R³ stands for an aryl group and R⁴ stands for analkylene group or a cycloalkylene group, comprising reacting anacetylene compound of the following formula (II): HC≡C—R⁴—C≡CH  (V)wherein R⁴ is as defined above, with a phosphorothioate of the followingformula (III): (R²O)₂P(═O)SR³  (III) wherein R² and R³ are as definedabove, in the presence of a palladium complex catalyst.
 3. Athioalkenylphosphonic acid ester of the following formula (I): R¹C(SR)═CHP(═O)(OR²)₂  (I) wherein R¹ stands for a monovalent group selectedfrom hydrogen atom, an alkyl group, a cycloalkyl group, a cycloalkenylgroup, an aryl group, an aralkyl group, an alkenyl group and a silylgroup and R² stands for an aryl group and R³ stands for an aryl group.4. A bis(thioalkenyl)phosphonic acid ester of the following formula(IV): [P(═O)(OR²)₂]CH═C(SR³)—R⁴—C(SR³)═CH[P(═O)(OR²)₂]  (IV) wherein R²stands for an aryl group, R³ stands for an aryl group and R⁴ stands foran alkylene group or a cycloalkylene group.